title: Antigenic analysis of influenza A viruses.
mesh_terms: D000956:Antigens, Viral / Q000032:analysis*; D006801:Humans; D009980:Influenza A virus / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology*; D014481:United States
chemical_list: D000956:Antigens, Viral